Soul Exchange

As an additional cost to cast this spell, exile a creature you control.
Return target creature card from your graveyard to the battlefield. Put a +2/+2 counter on that creature if the exiled creature was a Thrull.

Tevesh Szat, Doom of Fools

+2: Create two 0/1 black Thrull creature tokens.
+1: You may sacrifice another creature or planeswalker. If you do, draw two cards, then draw another card if the sacrificed permanent was a commander.
−10: Gain control of all commanders. Put all commanders from the command zone onto the battlefield under your control.
Tevesh Szat, Doom of Fools can be your commander.
Partner

Infernal Plunge

As an additional cost to cast this spell, sacrifice a creature.
Add {R}{R}{R}.

Mindstab Thrull

Whenever Mindstab Thrull attacks and isn't blocked, you may sacrifice it. If you do, defending player discards three cards.

Dark Ritual

Thrull Surgeon

{1}{B}, Sacrifice Thrull Surgeon: Look at target player's hand and choose a card from it. That player discards that card. Activate only as a sorcery.

Endrek Sahr, Master Breeder

Whenever you cast a creature spell, create X 1/1 black Thrull creature tokens, where X is that spell's mana value.
When you control seven or more Thrulls, sacrifice Endrek Sahr, Master Breeder.

Szat's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Each opponent sacrifices a creature they control with the greatest power.
• Exile all opponents' graveyards, then create X 0/1 black Thrull creature tokens, where X is the greatest power among creature cards exiled this way.

Endless Cockroaches

When Endless Cockroaches dies, return it to its owner's hand.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Body Snatcher

When Body Snatcher enters, exile it unless you discard a creature card.
When Body Snatcher dies, exile it and return target creature card from your graveyard to the battlefield.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Rograkh, Son of Rohgahh

First strike, menace, trample
Partner (You can have two commanders if both have partner.)